Microarray analysis of exosomal miRNAs from different liver cancer cells

To explore how tumor-derived exosomes activate fibroblasts and foster lung metastasis of liver cancer. MiRNAs encapsulated in exosomes are abundant and play an important role in cell-cell communication. Therefore, we hypothesized that tumor-derived exosomal miRNAs mediate fibroblasts activation. To identify the specific miRNAs involved, we conducted microarrays to generate miRNAs profiles of exosomes derived from the four liver cancer cell lines with different migration and invasion abilities. CSQT-2 and HCC-LM3 cells were high metastatic cancer cells, versus to HepG2 and MHCC-97L cells. We divided them into the following groups: CSQT-2 versus HepG2 (with different origins), HCC-LM3 versus MHCC-97L (with the same origin) and compared the up-regulated miRNAs in both two high-metastatic cancer cells-derived exosomes. Then, these up-regulated miRNAs were subjected to validation to define the most important exosomal miRNAs in regulating fibroblast activation and contributing to lung metastasis of liver cancer. Equal number of different cells were cultured with fresh DMEM supplemented serum which was depleted of exosomes for 48 hours and conditioned medium(CM) was collected for exosomes isolation.Three independent experiments were performed.